1. Field of the Invention
The present invention relates to an image pick-up device unit having an image pick-up device for obtaining an image signal corresponding to light irradiated on its photoelectrically converting surface and a camera having the image pick-up device unit. More specifically, the present invention relates to a camera, such as an interchangeable single-lens reflex digital camera, having a dust-proofing construction of the image pick-up device and an image pick-up device unit used for the camera.
2. Description of the Related Art
Recently, digital cameras such as a so-called digital still camera or a digital video camera (hereinafter, referred to as a digital camera or simply referred to as a camera) are generally put into practical use and are widespread. In the digital cameras, a subject image formed based on beams from a subject (hereinafter, referred to as subject beams), which are transmitted through a photographing optical system (also referred to as a photographing lens) is formed onto a photoelectrically converting surface of a solid image pick-up device arranged at a predetermined position, such as a CCD (Charge Coupled Device, hereinafter, simply referred to as an image pick-up device). Further, an electrical image signal or the like representing a desired subject image is generated by using an photoelectrically converting action of the image pick-up devices. A signal based on the image signal and the like are outputted to a predetermined display device such as an LCD (Liquid Crystal Display) and an image or the like is displayed. The image signal or the like generated by the image pick-up device is recorded to a predetermined recording area of a predetermined recording medium as predetermined-format image data. Further, the image data recorded to the recording medium is read and the image data is converted to become an image signal which is optimal for a display using the display device. Thereafter, an image corresponding thereto is displayed based on the processed image signal.
In general, digital cameras have an optical finder device for observing a desired subject prior to photographing, and for setting a photographing range including the subject.
In general, a so-called single-lens reflex finder device is used as the optical finder device. In this single-lens reflex finder device, the advancing direction of the subject beams transmitted through the photographing optical system is bent by using a reflecting member arranged on the optical axis of the photographing optical system such that the subject image for observation is formed at a predetermined position. On the other hand, upon a photographing operation, the reflecting member is evacuated from the optical axis of the photographing optical system, thereby guiding the subject beams onto a light receiving surface of the image pick-up device, that is, onto a photoelectrically converting surface thereof and forming the subject image for photographing on the photographically converting surface.
Furthermore, recently, a so-called interchangeable lens digital camera having the single-lens reflex finder device is generally put into practical use. In the interchangeable lens digital camera, the photographing optical system is detachable from a camera main body, and a plurality of types of photographing optical systems are selectively used in the single-camera main body by arbitrarily detaching and exchanging a desired photographing optical system in accordance with user's desire.
In the above-mentioned interchangeable lens digital camera, dust and the like floating in the air possibly enter the camera main body upon detaching the photographing optical system from the camera main body. Various mechanisms which are mechanically operated such as a shutter and a stop mechanism are arranged in the camera main body and thus, dangerously, the dust may interfere with the various mechanisms during the operation.
Upon detaching the photographing optical system from the camera main body, the light receiving surface (also referred to as the photoelectrically converting surface) of the image pick-up device arranged in the rear of the photographing optical system is exposed in the ambient air of the camera. Therefore, dust and the like adhere to the photoelectrically converting surface of the image pick-up device due to electrostatic charge action and the like.
Related art, for example, Japanese Unexamined Patent Application Publication No. 2000-29132 has proposed a technology for suppressing the adhesion of dust and the like to the light receiving surface of the image pick-up device due to the electrostatic charge action.
Means disclosed in Japanese Unexamined Patent Application Publication No. 2000-29132 suppresses the adhesion of dust and the like onto the light receiving surface of the image pick-up device due to the electrostatic charge action by providing a transparent electrode on the surface of a cover member for covering the light receiving surface of the image pick-up device provided in the camera and by applying to the transparent electrode a DC voltage or an AC voltage of several KHz to 20 kHz.
The means for neutralizing electric charges generated by the image pick-up device according to the above publication suppresses the adhesion of dust and the like onto the light receiving surface of the image pick-up device due to static electricity.
On the other hand, as the image pick-up device in the conventional digital cameras, a packaged image pick-up device (e.g., referred to as a packaged CCD) is widely used. In addition to the above-mentioned image pick-up device, recently, the supply of a so-called bare CCD chip is proposed.
For example, Japanese Unexamined Patent Application Publication No. 9-130654 discloses means for shaking off dust and the like which are adhered to the photoelectrically converting surface by providing a member for vibration such as a piezoelectric element between the bare chip CCD and a substrate on which the bare chip CCD is placed and by applying a predetermined voltage to the member for vibration because the dusts and the like are adhered onto the photoelectrically converting surface in the bare chip CCD in many cases.
Further, for example, Japanese Unexamined Patent Application Publication No. 2001-298640 proposes means for removing dust and the like adhered to the surface of an optical member such as a low-pass filter arranged in front of the image pick-up device in conventional interchangeable lens digital cameras.
The camera disclosed in Japanese Unexamined Patent Application Publication No. 2001-298640 comprises a wiper member as means for removing dust and the like adhered to the surface of the optical member arranged in front of the image pick-up device.
The wiper member grinds the surface of the optical member such as the low-pass filter and moves on the surface, thereby shaking off dust on the surface of the optical member, removing dust and the like adhered to the surface of the optical member. The dust and the like brushed off by the wiper are put into a groove portion of a camera main body, which is formed near the optical member.
However, the means disclosed in Japanese Unexamined Patent Application Publication No. 2000-29132 suppresses the adhesion of dust and the like by neutralizing electric charges of the charged image pick-up device. Consequently, the means is not optimal for removing dust which is adhered to the photoelectrically converting surface of the image pick-up device, irrespective of the static electricity.
Various factors are considered, for example, the adhesion of dust due to electrostatic force and the adhesion of dust independent of the electrostatic force. Further, the size of the adhered dust particles varies.
Moreover, the means disclosed in Japanese Unexamined Patent Application Publication No. 9-130654 cannot be optimal for applying to the image pick-up device such as the packaged CCD generally used for the conventional digital cameras because the means is devised in view of the bare chip CCD.
In other words, when the means disclosed in Japanese Unexamined Patent Application Publication No. 9-130654 is applied to the general packaged CCD or the like, vibrations to the image pick-up device or the package are applied. Thus, it is likely that the vibrating operation adversely influences various mechanisms arranged near the image pick-up device, for example, by causing the deterioration of mechanisms and the occurrence of errors.
Furthermore, the means disclosed in Japanese Unexamined Patent Application Publication No. 2001-298640 needs the wiper member and another member, such as a driving motor, for driving the wiper member. The arrangement of the members requires space in the camera. Therefore, there is a problem that the camera itself is increased in scale.